Visual Basic Programming Introduction• VB is one of the High level language• VB has evolved from the BASIC language. BASIC stands for Beginners All-purpose

Symbolic Instruction Code.• BASIC language is one of the CUI (Character User Interface) tool. In a CUI, you

interact with the computer application (program) by keying in commands.• But VB is one of the GUI (Graphical User Interface) tool. GUI s are easy to learn and

use you do not have to remember any command or syntax, most of the commands can be executed using the mouse.

• In VB, you can use a Form and Controls to create a user interface.• Form : is the main building block in a VB application. It is a base window on which

you can design the user interface.• Controls: are objects that are placed on the Form object to allow the user to interact

with the application. Each control has its own purpose and characteristics. These characteristics are called properties.

• Events : The user may click the mouse on various controls, or press a key or key combination on the user interface. These are known as Events

• Event-Driven Programming: The application developer must decide how the application must react to each of the user’s actions. This is called Event-Driven Programming

IDE ( Integrated Development Environment)

MENUS

The menu bar contains the commands you need to work with visual Basic. There are totally 13 menus in VB.

1.File 2.Edit 3.View 4.Project 5.Format 6.Debug 7.Run 8.Query 9.Diagram 10.Tools 11.Add-ins 12.Windows 13.Help

The FORM WINDOW

The Form Designer is the main window in the middle of the screen, and in it you

Design and edit the application’s user interface. It displays two windows for each Form:

–The Form itself (the element of the visible user interface)

–A Code window (the code behind the elements of the Forms)

THE PROJECT EXPLORER

The window titled Project is the Project Explorer, which displays the components of the project. It is organized in folders and it looks like Windows Explorer. It has ‘Object’, ‘Code’, ‘Toggle Folder’

The PROPERTIES WINDOW

It contains the property setting for the selected control. Properties are attributes of an object, such as its size, caption, and color. You can adjust the appearance of the controls on the Form with point-and-click appearance.

The FORM LAYOUT WINDOW

It is in the lower-right corner of the VB IDE, used to determine the initial positions of the Forms in your application. It is useful in applications that use multiple forms.

The IMMEDIATE WINDOW It is a debugging aid. While an application is running, you can stop it and use the Immediate Window to examine or change the values of the application’s variable and to execute. You can also use variable in the Immediate Window. If you enter the following lines:A=1888B=999Print a/b

You will see the result 1.889888The TOOLBOX It contains the icons of the controls you can place on a Form to create the application’s user interface. By default, the Toolbox contains the Pointer icon and the icons of 21 ActiveX controls. To place a control on a Form, you first select it with the mouse and then move the mouse over the form. When the mouse is over the form, the cursor turns into a cross, and you can draw the control on the Form.

1.Pointer 2. Label 3. Text Box 4.Command Button 5. Horizontal Scrollbar 6. Vertical Scrollbar 7. Check Box 8.Option Button 9.Frame 10.Combo Box 11. List Box 12. Timer 13.Drive List Box 14. Directory List Box 15. File List Box 16.Shape 17. Line 18. Image 19. Data 20.OLE 21. Picture Box

COMMON PROPERTIESThe following properties apply to most objects.

NAMEThis property sets the name of the controls.

BACKCOLORThis property sets the background color on which text is displayed or

graphics are drawn.FORECOLOR

This property sets the fore color (i.e. Text color)FONT

This property sets the font, font style, effects (strike out & underline) and size of the font used for the text on the control.CAPTION

This property sets the text that is displayed in many controls, for example Label control, string displayed next to the Checkbox and option button controls.VISIBLE

This property sets the controls to make visible/invisible during the execution of the program. (Default: True)WIDTH, HEIGHT

These properties set the control’s dimensions.LEFT, TOP

These properties set the co-ordinates of the control’s upper-left corner.

LABELThis control displays text on a Form that the user can’t edit. Labels commonly

identify other controls.Properties:

* Name * Back Color * Caption * ToolTipText * Visible * Font * Fore colorTEXT BOX

Sometimes called an ‘edit field’ or ‘edit control’ used for displaying and entering text and is the most common controls used in form designing. COMMAND BUTTON

It is also known as push Button, is one of the most commonly used controls in VB. It represents an action that is carried out when the user clicks the button. It is used to begin, interrupt, or end a particular process.Ex: Design a VB form to find area of circle.

Program:

Private Sub Command1_Click()

Text2.Text = 3.14 * Val(Text1.Text) * Val(Text1.Text)

End Sub

Ex: 2 Design a VB form to perform simple Arithmetic operations

ProgramPrivate Sub Addition_Click() c = Val(a) + Val(b)End SubPrivate Sub Division_Click() c = Val(a) / Val(b)End SubPrivate Sub Multiplication_Click() c = Val(a) * Val(b)End Sub

Private Sub Subtraction_Click() c = Val(a) - Val(b)End Sub

OPTION BUTTONIt is a round radio button that provides a set of choices from which a user can

select only one choice. Value: This property returns or sets the state of the OptionButtonValue: True False

This property returns True when an OptionButton is selected. And it returns False when it is not selected.Ex: Design a VB form to find simple and compound interest.

ProgramPrivate Sub Result_Click()

If Option1.Value = True Then

Text4.Text = Val(p) * Val(n) * Val(r) / 100

End If

If Option2.Value = True Then

Text4.Text = Val(p) * (1 + (Val(r) / 100)) ^ Val(n) - Val(p)

End If

End Sub

FRAME

Frame Control acts as a container for other controls, typically option buttons or Check boxes

CHECK BOX

It allows the user to select one or more options from a list of independent options. When you select the Checkbox control, it is checked and the square is filled with a check mark.

Value property :

This property is used to specify the state of a Check Box. If a Check Box is deselected it returns False or 0, if the check box is selected it returns True or 1

0 – Unchecked 1 – Checked

Example:

Program:Private Sub Check1_Click() If Check1.Value = 1 Then Label1.Font.Strikethrough = True ElseIf Check1.Value = 0 Then Label1.Font.Strikethrough = False End IfEnd SubPrivate Sub Check2_Click() If Check2.Value = 1 Then Label1.Font.Underline = True ElseIf Check2.Value = 0 Then Label1.Font.Underline = False End IfEnd Sub

Private Sub Check3_Click()

If Check3.Value = 0 Then

Label3.Font.Bold = False

ElseIf Check3.Value = 1 Then

Label1.Font.Bold = True

End If

End Sub

Private Sub Check4_Click()

If Check4.Value = 1 Then

Label1.Font.Italic = True

ElseIf Check4.Value = 0 Then

Label1.Font.Italic = False

End If

End Sub

LIST BOX

List Box control present a set of choices that are displayed vertically in a single column. Scrollbar will automatically appear on the control if the items exceed the value that can be displayed.List property

To add items in the list at design time we use this property. To add items in design time click ‘List’ and then add items. Press CTRL + ENTER after adding each item

METHODS

Adding items to a List

We can add items to the List at design or at run time.

1.Design time :

Refer ‘list’ property.

2.Run time :

The ‘AddItem’ method is used to add items to a list at run time.

Syntax:

Object.AddItem item, index

Where, item is a string that represents the text to add to the list.

Example:1

List1.Additem “India”

Example:2

For I = 1 to 10

A(i) = inputBox (“Enter the value”)

List1.AddItem a(i)

Next i

Removing items from a list

The ‘removeItem’ method is used to remove an item from a list.

Syntax

Object.RemoveItem index

Clear

This clear method removes al the items from the controls.

Syntax:

List1.clear

ListCount

This is the method is used to count the total number of items.

Ex: Design a VB form to find maximum and minimum elements from set of N numbers also print its position

ProgramDim A(10) As IntegerDim I, N, J,Min,Max,minpos,maxpos As IntegerPrivate Sub Input_Click()N = InputBox("ENTER HOW MANY NUMBERS")For I = 1 To NA(I) = InputBox("ENTER THE NUMBER")List1.AddItem A(I)Next IEnd Sub

Private Sub Result_Click() Max = A(1)

maxpos = 1Min = A(1)minpos = 1For I = 1 To N

If A(I) > Max Then Max = A(I)

maxpos = I End If If A(I) < Min Then

Min = A(I)minpos = I

End If Next I

Text1.Text = MaxText2.Text = maxposText3.Text = MinText4.Text = minpos

End Sub